Best charging practices for battery longevity

[jray3]

If you do not have a Remote, then a simple mechanical timer (e.g., 6-hour) can do the same thing - that's what I primarily use.

Ah yes Joe, but does your wife happily perform mental calculations and set the timer? My 100% daily charge is an integral part of spousal EV acceptance.

 

[JoeS]

If you do not have a Remote, then a simple mechanical timer (e.g., 6-hour) can do the same thing - that's what I primarily use.

Ah yes Joe, but does your wife happily perform mental calculations and set the timer? My 100% daily charge is an integral part of spousal EV acceptance.

Incredible as it may seem, she really does and is actually very good at judging how much time is needed to bring the charge back up to 12 bars (and this is a person with a History degree for whom math is a foreign language). I'm soooo lucky, and she loves her i-MiEV!

 

[9h1bw]

Thank you for that information. I have an accurate data of the charging process. I will first try how the remote works.

 

[pbui19]

My wife has a degree in physics and there is no way she'll be using that timer, go figure

 

[pbui19]

I am experimenting with a new ChargePoint Home Station, mainly to participate in the pilot submetering program with our electric company here in Northern CA. It was a pleasant surprise to discover that I can set the station start/end time via a cell phone app. So I am thinking, if I can figure out how to broadcast the SOC, I may be able to use ifttt.com (If-This-Then-That) service to send command to terminate charging. I just discover ifttt.com and have yet to use it, it's a web service providing applets to send command between apps. I recall reading somewhere on this forum having set up a way to terminate at 80%. Hopefully my first application with ifttt will occur promptly, as I am awaiting delivery of a wifi connection to my heat pump water heater. I like to avoid running it during peak cost hours.

Our BoltEV has a "Hill Top" setting, but it's at 90%. If real summer ever comes to northern CA; 90% SOC in the heat is a bit too high. Though the BoltEV has active thermal control.

Thanks for the link suggesting the reason why the 12v aux battery dies in an EV. I often wonder why these SLA batteries died in UPS application. Perhaps a LiFePo 12v aux is a better choice ? given that EV "engine" compartment doesn't get very hot anyway. But I guess I would design a large enough capacity to keep "full" at about 75% of max SOC.

...sorry for the rambling

 

[RobbW]

I pretty much plug in my Meepster and charge daily. I use the remote to schedule the start time for just after midnight to take advantage of low overnight electric rates. Depending on the season and the temperature, the Meepster will have just finished charging right before I need to leave for work (winter months and the cold shoulders of spring/fall), or will have finished up long ago (warm, summer months). When I first got my i-MiEV 4 years ago, I was much more OCD about trying to use the best charging practices. These days, I just plug it in and let the remote schedule have its way with her.

However, now that I just got my new Pacifica eHybrid, the old OCD may be rearing its ugly head again!

 

[Phximiev]

However, now that I just got my new Pacifica eHybrid, the old OCD may be rearing its ugly head again!

And how is the Pacifica working out? We were thinking of that but got the Volt instead.

 

[RobbW]

However, now that I just got my new Pacifica eHybrid, the old OCD may be rearing its ugly head again!

And how is the Pacifica working out? We were thinking of that but got the Volt instead.

We freaking love the Pacifica Hybrid!!!!!!! (Can't give it enough exclamation points). I would have loved to have gotten another all-EV, especially one with significantly more range like the Bolt or the upcoming Tesla Model 3. However, we were replacing our Toyota Sienna minivan and needed a similar vehicle. This is the car we use when we need to drive farther than our Meepster can go or when we need to haul more people or cargo than the Meepster can hold. Also, I need a vehicle to which I could strap my sea kayak on top and throw all my paddling gear in the rear. Now that we have the Pacifica Hybrid with all its features that make the kids happy, we may actually consider starting to take more road trips. I just always hated driving our Sienna with its craptastic 18-20 mpg! The estimated 82 MPGe of the Pacifica Hybrid is much easier to stomach for those longer drives!

 

[Phximiev]

However, now that I just got my new Pacifica eHybrid, the old OCD may be rearing its ugly head again!

And how is the Pacifica working out? We were thinking of that but got the Volt instead.

We freaking love the Pacifica Hybrid!!!!!!! (Can't give it enough exclamation points). I would have loved to have gotten another all-EV, especially one with significantly more range like the Bolt or the upcoming Tesla Model 3. However, we were replacing our Toyota Sienna minivan and needed a similar vehicle. This is the car we use when we need to drive farther than our Meepster can go or when we need to haul more people or cargo than the Meepster can hold. Also, I need a vehicle to which I could strap my sea kayak on top and throw all my paddling gear in the rear. Now that we have the Pacifica Hybrid with all its features that make the kids happy, we may actually consider starting to take more road trips. I just always hated driving our Sienna with its craptastic 18-20 mpg! The estimated 82 MPGe of the Pacifica Hybrid is much easier to stomach for those longer drives!

Buy or lease? Options? Are you getting the 33 miles of electric range? Attitude at dealers?

Admin: Perhaps we need a new topic?

 

[zzcoopej]

I would have loved to have gotten another all-EV, especially one with significantly more range like the Bolt or the upcoming Tesla Model 3. However, we were replacing our Toyota Sienna minivan and needed a similar vehicle. This is the car we use when we need to drive farther than our Meepster can go or when we need to haul more people or cargo than the Meepster can hold. Also, I need a vehicle to which I could strap my sea kayak on top and throw all my paddling gear in the rear.

Its a real pity the Outlander PHEV is not available over there in USA as its a perfect 2nd car to the iMiEV. And like you, I kayak too!

 

[pbui19]

I just re-read this thread for the same reason as the title, but for a BoltEV application. Let's say if the iMiev has a 60kwh pack and your typical daily usage only needs 16kwh, about 60-miles, or about 25% of the pack capacity.

What is the recommended SOC % to hover around for daily charging ? some says 50% but I haven't been able to confirm. Which is better:

1. Leave at 75%, return at 50% and charge up to 75%
2. Leave at 65%, return at 40%

or am I chasing after gnats ? My understanding is that it's better to shallow charge and stay away from 100% for long duration.

Thanks

 

[Don]

or am I chasing after gnats ? My understanding is that it's better to shallow charge and stay away from 100% for long duration.

I think so. Discharging to around 20% and then recharging to around 80% is all I would try to adhere to. Sounds like you may be able to charge every 3rd, 4th or even 5th day and be just fine. When you need a 'full' charge I wouldn't hesitate to do that - It's a good idea to recharge fully at least once every 6 weeks or so anyway

Don

 

[JoeS]

...
2. Leave at 65%, return at 40%
or am I chasing after gnats ? ...

Yes to both, as I'd personally prefer to let the car sip a bit of juice every day while keeping the SoC around the midpoint. Mostly uneducated opinion based on both reading about the subject and interacting with people working in the field... my impression is that operating at an even lower SoC is better for longevity. My understanding is that as long as the battery is kept away from either extreme of SoC, such longevity extension benefits are minor. Need to research the technical literature to see what the latest controlled test data results yield. Perhaps more significant is the battery thermal control while the car is not being driven?

<Rant>Pity that the way our society is structured that the world's experts on the subject (outside the academic lab environment) are captive to corporations and, of necessity, tight-lipped, so it is difficult to find out what indeed would be the best practice in this example. Wouldn't it be wonderful if a battery expert from LG Chem or GM would be allowed to directly answer this question?</Rant>

 

[PV1]

Anywhere in the 20-80% charge range should be more than fine for extending life. The I-MiEV's full charge is actually about 90% real SoC (4.1 volts per cell), so even allowing the car to fully charge shouldn't dramatically affect battery longevity (though sitting there for extended periods may). On my Dell laptop, I trimmed the charge back from a full charge of 4.35 volts per cell to 4.15 volts and this has all but stopped cell degradation (noting that laptops over-charge their batteries and that li-ion should only go to 4.2 volts max).

With the Bolt specifically, enabling Hill Top Reserve will make the car stop at 88% charge. I tend to leave this enabled and charge once a week unless I need the range, like I did yesterday. I run the Bolt between 30% and 88% charge most of the time, as my driving takes all week to drain it down that far. A side benefit for me (which is the main point of the feature) is that regen is not limited by high SoC when HTR is enabled.

 

[Don]

Pity that the way our society is structured that the world's experts on the subject (outside the academic lab environment) are captive to corporations and, of necessity, tight-lipped, so it is difficult to find out what indeed would be the best practice in this example. Wouldn't it be wonderful if a battery expert from LG Chem or GM would be allowed to directly answer this question?

What they disclose to the public is all marketing - They'll say whatever they think will help sell their product

For example, my gas burning Ford Transit Connect has a 6 speed automatic that Ford says is 'maintenance free' for the first 100K, despite the fact that many owners have found out the hard way that a significant number of those transmissions will need either a replacement or a major repair well before the 100K mark - They'll likely make it to the end of the factory warranty period, but that's about it. The really sad part? They didn't even bother to fill it with synthetic at the factory . . . . . synthetic lube in the engine, but not in the '100K transmission'

The wise consumer had better either pay a big bundle for the extended warranty or do some research about common sense solutions before they have to pony up $3K or more for a new transmission

EV owners on the other hand seem to be a more educated bunch and are keeping up with the latest info available on their product . . . . and we understand that much of the marketing on our cars was done in an attempt to make the car seem as 'normal' in everyday use as the gassers most of us grew up driving. Why this is being done, I'm not sure. Many of us were looking to buy something as different from the traditional ICE's as we could find and really, really wish more common sense explaining why 'different' in this case is actually 'better'

Don

 

[pbui19]

thanks for all replies. I did find this yesterday

"..• 75–65% SoC offers longest cycle life
• EVs use 85–25% SoC to prolong battery life
• 100–25% SoC gives long runtime, makes best use of battery, but reduces battery life."

at this web site:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

in the text just below Fig 6.

====================
Joes ...
"....Perhaps more significant is the battery thermal control while the car is not being driven? "

There is indication that the BoltEV TMS will turn on, such as running the AC to cool the pack, while off and parked. Of course, then one would wonder whether there is a minimum SOC when such management ceases to prevent draining the pack too low. Imagine parking the Bolt for a month at a hot airport for a month, then coming back to a drained pack.

 

[JoeS]

Found the results of a recent study over on the mychevybolt.com forum, showing that simply delaying charging until just before leaving ("As Late As Possible") can double battery life compared with frequent and full recharging.

Here's their thread:

http://www.mychevybolt.com/forum/viewtopic.php?f=12&t=8080#

Here's the study they reference - I couldn't figure out how to access it without paying -

https://doi.org/10.1016/j.trb.2018.03.016